Electric Drives and Control

Which of the following type electric drive is used in cranes?

• Individual

• Multimotor

• Group

• None of the Above

Which of the following is the basic elements of a electric drive?

• Control system

• Electric motor

• Both

• None of the above

The selection of an electric motor for any application depends on which of the following factors?

• Electrical Characteristics

• Mechanical Characteristic

• Size and rating of the motors

• All

The load cycle for a motor driving a power press will be

• Variable load.

• Continuous load

• Continuous but periodic.

• Intermittent and variable load.

Example for continuous duty ______

• Paper mill drive

• Conveyers

• Fan

• All

Example for short time duty_______

• Crane drive

• Pressing

• Cutting

• Drilling

What will happen if the back emf of a DC motor vanishes suddenly?

• The motor will stop

• The motor will continue to run

• The armature may burn

• The motor will run noisy

What will happen, with the increase in speed of a DC motor?

• Back emf increase but line current falls.

• Back emf falls and line current increase.

• Both back emf as well as line current increase.

• Both back emf as well as line current fall.

Which part will surely tell that given motor is DC motor and not an AC type?

• Winding

• Shaft

• Commutator

• Stator

Direction of rotation of motor is determined by

• Faraday’s law

• Lenz’s law

• Coulomb’s law

• Fleming’s left-hand rule